Four varieties of Italian ryegrass (Lolium multiflorum), which have been found to differ in voluntary intake by livestock at the same level of digestibility, were examined in the year of sowing and in the two subsequent years in a field experiment. Eight dates of first harvest during May–June in the years after the year of sowing were compared. During May–June in these years the proportion of leaf in the crop was closely related to the stage of development of the crop relative to heading date, whereas yield and digestibility were more closely related to calendar date. As a result the later-heading varieties, S. 22 and Sabalan, had a higher proportion of leaf than the earlier-heading varieties, RvP and Tetila Tetrone, at a given yield and digestibility and this may at least partly account for higher intake in the former varieties. In addition, in Sabalan, the proportion of green leaf relative to dead was particularly high and the proportion of cell wall particularly low. The surface area per unit dry weight of leaf blade was much higher than that of ‘stem’, which may contribute to shorter retention time in the reticulo-rumen. Surface area per unit weight of both leaf blade and ‘stem’ declined with delay in date of first harvest.

The yield of RvP relative to the other varieties was modest at the first harvest in the years after the year of sowing and high at subsequent harvests, in accord with National Institute of Agricultural Botany results. The high yield of RvP relative to the other varieties after the first harvest appeared to be associated with a relatively large number of tillers with their shoot apex below cutting height at the time of first harvest. It seemed that most of these tillers had emerged during the few weeks before that harvest. The proportion of tillers with their shoot apex below rather than above cutting height at the time of first harvest was higher in all four varieties than casual observation would suggest and the proportion remained rather high throughout May and June. The rapid rate of turnover of tillers in Italian ryegrass was confirmed.

No correlation was found between the seed yield per plant of oil-seed rape, the percentage of podless stalks and the percentage of pods infested with seed weevil larvae. The weight per seed and the percentage of podless stalks of winter and spring rape plants were similar.

In winter crops the mean number of seeds per plant, weight of seeds per plant, and number of pods per plant were greater near the crop centre than near the crop edge. Plants with relatively few seeds tend to compensate by having heavier ones.

Pods infested with seed weevil had fewer and lighter seeds than pods not infested, but the overall decrease in weight of seed per pod was small. The proportion of pods infested with seed weevil in winter rape was twice that in spring rape plants, but was not great. In lightly infested fields the weevils were concentrated at the edges, but the opposite occurred as infestation increased.

Infestation of pods of winter rape by seed weevil increased with the number of years rape had been grown on the farm. There was no correlation between insecticide application and yield, but the number of insecticide applications to spring rape crops was positively correlated with the number of years for which the farmer had grown rape.

Two group-feeding and one individual-feeding experiments were made for 112 and 182 days, respectively, with 76 cross-bred and eight Zebu bulls. Simmental, Friesian and Jersey sire breeds were mated to three Ethiopian Zebu breeds, namely Boran, Horro and Barca, while Zebu bulls were included for comparison purposes in Expt 3. The trials were conducted in confinement at Holetta Research Station, located at 2400 m elevation and having a mean maximum temperature range of 18·7–24 °C. In the group-feeding trials (Expts 1 and 2) a common diet was fed, consisting of native hay (30%) molasses (20%) and a concentrate supplement. In the third experiment, two diets containing 30 and 50% native hay were supplemented by concentrate and fed individually to eight Simmental and eight Friesian cross bulls, while eight Zebus served as a control.

The average daily gains, feed intake and conversion did not differ markedly between Simmental and Friesian crosses, but lower values were generally found for Jersey crosses. Cross-breds outgained Zebus, consumed more feed and converted it more efficiently to live-weight gain. Performance differences were noted between the Zebu breeds as well as some evidence of sire × dam breed interactions. Significantly higher gains were achieved with the low than with the high roughage diet.

Two fattening experiments are reported with 60 cross-bred bulls. In the first experiment three pen groups (9–16 months old) of eight Simmental, eight Friesian and eight Jersey crosses, from Boran and Barca dams, were fed for 98 days on a common diet consisting of maize cobs, molasses and concentrate. There were no significant differences among sire or dam breeds, with the Barca cross bulls performing non-significantly better than the Boran crosses. Simmentals and Friesians consumed about the same amount of feed and the latter were the most efficient feed converters. In the second experiment, 36 bulls ranging from 11 to 18 months of age were fed for 51 days diets consisting of either 30 or 50% maize stalks and concentrate; maize stalks were replaced by maize/sorghum silage for the next 61 days. There were no significant differences in rate of gain between sire breeds. Bulls from Boran dams gained faster (P < 0·01) than those from Horro dams while a higher (P < 0·05) daily gain was recorded for the diet with the lower than with the higher percentage of maize stalks.

Thirty-nine adult ewes of identical body size and age were randomly taken from the Chokla breed. They were divided into four groups which were allowed water once in 24, 48, 72 and 96 h. Seven ewes from each of the first, third and fourth groups were mated for the first time in the spring and for a second time in winter, so that they lambed in the monsoon and summer season respectively. All the ewes were maintained on uncultivated pasture. Watering once in 72 and 96 h caused body weight loss up to 26%, compared with those watered daily. The ewes which failed to maintain pregnancy lost more than 30% of their body weights due to watering only once in 96 h and there were about 43 and 100% lambing in the first and second breeding cycle of the same ewes. The remaining groups displayed 100% lambing. The water-intake increased significantly in the third month of pregnancy in the group allowed water daily and water consumption was found to be about 13% of body weight, whereas the values for those watered once in 72 and 96 h were 9 and 8% respectively. The water-deprived animals were able to drink up to 32 % of their body weights within 2–3 min. It is concluded that breeding ewes could be watered once in 72 h without any loss of lambing during summer.

A field experiment was made in the wheat growing season (November–April) of 1973–4 at the Indian Agricultural Research Institute, New Delhi, to compare pure and systematic mixed stands of three wheat genotypes differing in plant height. The systematic mixed stands were made to give prismatic and columnar canopy patterns. Grain yield of wheat was significantly greater in the mixed stands than the mean yield in the pure stands; the two mixed stands did not differ significantly. The grain yield in the mixed stands was almost the same or slightly more than that of the largest yielding genotype in its pure stand. When grown in the mixed stand the tall genotype yielded more than in a pure stand but the dwarf genotype yielded less.

It is generally assumed that poorly filled, or shrivelled wheat grain gives poor flour yields on milling, due to low endosperm content. Quality standards therefore often impose minimum limits of specific weight and grain size with the intention of excluding shrivelled samples. Although milling and baking quality are partly genetically determined, certain of their components are strongly influenced by environment. Flour protein, loaf score and alpha-amylase activity may be improved by nitrogen fertilizer (Pushman & Bingham, 1976), although the reaction of other characters is sometimes less favourable. Reduced flour yields and deterioration of flour colour have been reported at high rates of nitrogen fertilizer (Fuller & Stewart, 1968), and grains frequently become smaller and more shrivelled as application rate is increased (Bayles, 1977 c).